Acoustic device



Dec. 25, 1934. J. R ERlCKSQN 1,985,722

ACOUSTIC DEVICE Filed March lO, 1932 2 Sheets-Sheet l F/G. l

/a l I7 /0 FIG. 2

Dec. 25, 1934. J. R. ERICKSON 1,985,722

ACOUSTIC DEVICE Filed March 1o, 1932 sheets-sheet 2 y 47 W/z 'W/ /N VEN TOR J. R. ER/CKSON BV ,v f

om@ A TTOR/VEV Patented Dec. 25,. 1934 UNITED STATES PATENT OFFICE Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application March 10, `1932, Serial No. 597,879

9 Claims.

diaphragm may be obtained and maintained. A

tightly clamped diaphragm, however, does not readily adjust itself to temperature changes, and undesirable strain conditions occur in the diaphragm which impair quality and eflicient reproduction. Furthermore, a tightly clamped diaphragm cannot clearly reproduce the voice currents conducted to the receiver because of the restraint on its freedom of movement.

It has been proposed to provide a telephone receiver with a floating diaphragm and thereby overcome these objections. The diaphragm is mounted so as to be peripherally free between a plurality of metal or paper damping washers, these washers being disposed in an annular, U- section channel member. Such an arrangement, however, is not conducive to the obtaining and the maintenance of the proper and desirable spacing between the pole faces of the magnetic unit of the receiver and the diaphragm. Furthermore, such an arrangement, although readily detachable, is, not convenient to manufacture or to assemble; nor may the diaphragm unit or assembly be used as an interchangeable unit in receivers of the same type because of the manner in which the diaphragm is mounted within the channel member and between the paper washers.

An object of this invention is to enable the use 40 of a peripherally free diaphragm in a telephone receiver, and yet avoid undesirable variations in the spacing between the pole faces and the diaphragm. l

Another object of this invention is to provide a telephone receiver with a readily assembled diaphragm unit or assembly comprising a peripherally free diaphragm, which unit or assembly is readily interchangeable in receivers of a similar type.

It has been found desirable sometimes, however, to hold the peripheral portion of a receiver diaphragm between clamping surfaces and to apply damping to one or each surface of the diaphragm. This invention may be employed with diaphragms so mounted, also.

Another object of this invention, therefore, is to support a peripherally constrained, damped diaphragm in a unit or assembly which is detachable as such from an acoustic device.

A feature of this invention comprises supporting or mounting a telephone receiver diaphragm so that it is peripherally free and yet has one surface separated a predetermined distance from a pole piece of the receiver.

Another feature ,of this invention comprises supporting or mounting a diaphragm, or a peripherally free diaphragm, or a peripherally free damped diaphragm, between a pair of flat plates, or disc members, eachhaving a central opening and being secured together, the plane of one surface of the diaphragm being in a plane of one of the plate members, or in the plane of the adjacent surfaces of the plate members, or in the plane of the rim portion of the case of an acoustic device.

Still another feature of this invention comprises supporting or mounting a diaphragm between a pair of plate, fiat, or disc members, each having a central opening and being secured together, the plate members being of different sizes to provide a ledge or rim portion for engagement with the rim portion of a case of an acoustic device.

A further feature of this invention comprises supporting or mounting a diaphragm between a pair of flat, plate or disc members, each having a central opening and being secured together, the

plates being substantially annular andbeing of different outside diameters, so as to provide a ledge or rim portion for engagement with the rim portion of a receiver case, which case contains a pole piece whose face has been ground with reference to the case rim, one surface of the diaphragm being in the plane of the case rim.

One embodiment of this invention comprises a telephone receiver having a case, or casing, provided with a rim portion and containing a magnetic unit comprising a permanent magnet and al pair of pole pieces, each pole piece being surrounded by an energizing coil. The faces of the pole pieces are ground with reference to the rim of the receiver case so that a desired separation exists between the planes of the rim and of the pole faces. A diaphragm unit or assembly comprising a pair of flat plates, or disc members and a vibratable member or diaphragm is supported on the `case rim. The plate members, preferably substantially annular in shape, have each a central opening, are of different outside diameters, and are secured together to provide a substantially annular rim or ledge portion engaging with introduces a considerable compressive force at the peripheral portion of the diaphragm.

The receiver of Fig. 7 is similar to the receiver of Figs. l to fi, the permanent magnet and pole pieces or cores being molded integrally with the casing 46. The energizing coils are held on the cores by the non-magnetic plate di'.

Although the features of this invention have been disclosed with reference to various specific structures, it is understood, of course, that vaa rious modiiications may be made in the details oi' construction without departing from the scope of the invention as defined in the appended claims.

What is claiimedl is: l

l. A telephone receiver comprising a case hav:D ing an open end dened by a rim portion, diaphragm, and means enclosing said clac phragm, said means comprising a pair o plates of different sizes, said plates being seemed ton gether to form a ledge portion los engagement with the rim of said case, each oi said plates having an opening therein and one of said being located within said case and depending v from the other plate. V

2. A telephone receiver comprising a case lleva ing an open end defined by a rim portion, e. diag phragm, and means enclosing said said means comprising a pair oi plates ci difiere ent sizes, and diaphragm vibration controlling means between one of said plates and the pes ripheral portion of said diaphragm, anch plates being secured together to form a ledge portion for engagement with the rim of the case, of the plates having an opening and said die phragm being supported entirely inside oi the rim of the case.

3. A telephone receiver comprising a case hav' ing an open end deilned by a rim portion, a diaphragm, and means enclosing saiddiaphragm, said means comprising a pair of plates of different sizes, said plates being secured together to form a ledge portion for engagement with the rim of the case, one plateronly engaging with said rim, the other plate being within said rim and depending from the iirst mentioned plate, each of said plates having an opening and one of said plates having a recess therein in which the diaphragm is positioned.

4. A telephone receiver comprising a case having an open end deined by a rim portion, an earpiece engaging with said case and covering said open end, a diaphragm, means between said earpiece and said case enclosing said diaphragm, said means comprising a pair of plates of different sizes, one only of said plates being held between the earpiece and case rim, the other of said plates depending from the rst mentioned plate, each of said plates having an opening..

5. A telephone receiver comprising a ease have forming a ledge portion fior engagement t ing an open end deed by a rim portionn a diesl phragrn, and means enclosing said diaphragm, said means comprising a pair of plates oi? dit@ ferent aises, said plates being secured together to torni a ledge portion for engagement with the rim ol said case, each of the plates having" opening, said diaphragm beine,r smaller than the open end of said. case and being supported so that one smface is in the plane of the case rim.,

A telephone receiver comprising a case ing an open end donned by a rim a phragm, and means enclosing said die-.piero m., said means comprising a pair'o plomo off i ent sizes, said plates being secured ot said case, of said plates having opening, said rim. he g a plurality ot recesses 'there-ln. and one of. said plates having like number similarly projections, or recesses projections heine auch the plates moet occupy a predates mined in order for the recesses and. prom lections to be ln alii-grinnent.

t'. A telephone receiver comprising case, eleca troroagnetie comprlsmg a pole piece theren said oase rino portion, the face ot said pole piece having been ground with refer:

ence to plate member having a conm' open a peripheral portion supported on said rlzn, another pla member having central opening and being secured to and depending from the ndi-st plate member, and a diaphragm between plate members, said diaphragm being sobstantiallg,v free to move at its peripheral portion.

S. A telephone receiver comprising a case, a diaphragm, electromagnetic means in the case to actuate the diaphragm, and means to mot said diaphragm on said case, said means cone prising a plurality of plate members, the peripheral portion of one of which restson said case, each of said members having a central opening, one of said members having a recessed portion within which the diaphragm ts and within which it is substantially free to move, the other of said members being secured to and depending from the iirst and providing a support for the rim portion of the diaphragm.

9. A telephone receiver including a case have ing an open vend dened by a substantially ane nular rim portion, a pole piece whose race has been ground with reference to said rim. a dia-u phragm, and a unitary aembiiv for said dia phragm comprising a pair oi annular plate members o'f diderent diameters secured together with'the diaphragm therebetween, a portion oi' one surface oi the larger only of said plate mem=l bers being adapted to engage with the case rim.

J@ R. N.

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